We made a twin track marble run, with a Calliope Mini running automation to take the marble back up to the top of the marble run each time.
The Calliope Mini is an evolution of the BBC Micro:bit, that is used in schools in Germany. It has all the functions of the Micro:bit, but with various useful extras added. We made use of the on board motor driver here to drive a Fischertechnik solar motor backwards and forwards, to raise the marble up to the top of our marble run automatically.
We installed a light sensor to detect the marble arriving down into the transport carts, and switches at the top of the lifting cart run to detect the cart at the top and switch off the motor.
https://www.youtube.com/channel/UCLU6sbBJymI6DzcHdyMMH_w
We programmed the Calliope in Open Roberta. Here is the program:
and here is the Open Roberta Calliope configuration:
The wiring setup is rather similar to the opening gate (Autoschranke) project in the Fischertechnik Calliope Kit :
https://www.fischertechnik.de/en/products/teaching/stem-robotics/544626-calliope